Adakite-gabbro-anorthosite magmatism at the final (576–546 Ma) development stage of the Neoproterozoic active margin in the south-west of the Siberian craton

Abstract

In the late Neoproterozoic a prolonged active continental margin mode dominated the southwestern margin of the Siberian craton. Based on results of geological, petrological-geochemical, U–Th–Pb and Sm–Nd, Rb–Sr isotope investigations, for the first time we established that on the final evolution stage of this margin 576–546 Ma, intrusions of adakites and gabbro-anorthosites of the Zimoveyniy massif were emplaced in the South Yenisei Ridge. These new data indicate genetic relationships of the studied adakites and host NEB-metabasites. The formation of adakites could have been due to a crustal or a mantle-crustal source in a setting of transform sliding of lithospheric plates after the subduction stopped.